ANTH-B 200 Lecture Notes - Lecture 30: Main Source, Rickets, Dark Skin
Document Summary
Provide a detailed explanation of the hypotheses that explain this distribution. Regulation of body temperature (through dilation or contraction of surface blood vessels which changes heat radiation, and through evaporation of sweat from sweat glands). Biology of skin color: there is a strong genetic component, and skin color is also affected by the environment (sunlight & tanning). Melanin is responsible for most of the variation in lightness or darkness of skin color. Melanin is a pigment secreted by cells (melanocytes) in the bottom layer of skin. Everyone (including albinos) have the same number of melanin-producing cells (melanocytes), but vary in the amounts and clustering of melanin produced by those cells. Hemoglobin (hb) also pigments the skin, because oxygenated blood is red due to. Lighter skinned people have less melanin near the surface of the skin, so the reddish color of their melanin shows through. iron in hb. Carotene is a yellowish pigment obtained from certain foods.
